diff --git a/app/helpers/dates_helper.rb b/app/helpers/dates_helper.rb
index eb57dfd..d54af52 100644
--- a/app/helpers/dates_helper.rb
+++ b/app/helpers/dates_helper.rb
@@ -46,7 +46,7 @@ module DatesHelper
     if (date1 == date2) || (date2.nil?)
       show_date(date1)
     else
-      _('from %s to %s') % [show_date(date1), show_date(date2)]
+      _('from %{date1} to %{date2}') % {:date1 => show_date(date1), :date2 => show_date(date2)}
     end
   end
 
diff --git a/test/unit/dates_helper_test.rb b/test/unit/dates_helper_test.rb
index 87b2e65..1370c5b 100644
--- a/test/unit/dates_helper_test.rb
+++ b/test/unit/dates_helper_test.rb
@@ -20,7 +20,7 @@ class DatesHelperTest < Test::Unit::TestCase
     expects(:show_date).with(date1).returns('XXX')
     date2 = mock
     expects(:show_date).with(date2).returns('YYY')
-    expects(:_).with('from %s to %s').returns('from %s to %s')
+    expects(:_).with('from %{date1} to %{date2}').returns('from %{date1} to %{date2}')
     assert_equal 'from XXX to YYY', show_period(date1, date2)
   end
 
@@ -36,6 +36,18 @@ class DatesHelperTest < Test::Unit::TestCase
     assert_equal 'XXX', show_period(date1)
   end
 
+  should 'not crash with events that have start_date and end_date' do
+    FastGettext.default_text_domain = 'noosferofull'
+    assert_nothing_raised do
+      Noosfero.locales.keys.each do |key|
+        Noosfero.with_locale(key) do
+          show_period(Date.today, Date.tomorrow)
+        end
+      end
+    end
+    FastGettext.default_text_domain = 'noosferotest'
+  end
+
   should 'show day of week' do
     expects(:_).with("Sunday").returns("Domingo")
     date = mock
--
libgit2 0.21.2